fish: tiger_g4e bottle secretly depends on gcc formula being installed and linked

[smammy]

Steps to replicate:

1. Be using a G4e machine.
2. Be running Tiger.
3. brew install --bottle fish
4. brew unlink gcc
5. fish

Expected result

Welcome to fish, the friendly interactive shell

Actual result

dyld: Symbol not found: __ZNSt7__cxx1112basic_stringIwSt11char_traitsIwESaIwEED1Ev
  Referenced from: /usr/local/bin/fish
  Expected in: /usr/lib/libstdc++.6.dylib

fish: 'fish' terminated by signal SIGTRAP (Trace or breakpoint trap)

Notes

• I haven't tried building fish from source with gcc unlinked.
• I don't know what library exactly dyld is missing, but I imagine it might be /usr/local/lib/gcc/7/libstdc++.6.dylib.

Output of `brew --config`

HOMEBREW_VERSION: 0.9.5
ORIGIN: https://github.com/mistydemeo/tigerbrew.git
HEAD: 1508070c8a2d42bf915e8597efd7b46ecb72fa6e
Last commit: 8 weeks ago
HOMEBREW_PREFIX: /usr/local
HOMEBREW_REPOSITORY: /usr/local
HOMEBREW_CELLAR: /usr/local/Cellar
HOMEBREW_BOTTLE_DOMAIN: https://ia904500.us.archive.org/24/items/tigerbrew
CPU: single-core 32-bit g4e
OS X: 10.4.11-Power Macintosh
Curl: /usr/local/Library/Homebrew/vendor/portable-curl/current/bin/curl
Xcode: 2.5
CLT: N/A
GCC-4.0: build 5370
GCC-4.2: build 5553
Clang: N/A
X11: 1.1.3 => /usr/X11R6
System Ruby: 2.3.3-222 => /usr/local/Library/Homebrew/vendor/portable-ruby/2.3.3/bin/ruby
Perl: /usr/local/opt/perl/bin/perl => /usr/local/Cellar/perl/5.40.0/bin/perl
Python: /usr/bin/python => /System/Library/Frameworks/Python.framework/Versions/2.3/bin/python
Ruby: /usr/bin/ruby => /Users/sam
Java: N/A

Output of `brew doctor`

Warning: You have unlinked kegs in your Cellar
Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
those kegs to fail to run properly once built. Run `brew link` on these:
    ghc70

[mistydemeo]

Sorry about this! fish requires a compiler with newer C++ support to build, so it must have transparently fallen back to building with a brewed GCC and I missed it. I'll fix this dependency.